Carbon nanotubes may be used in a variety of different applications such as sensors, supercapacitors, electrodes, drug-delivery, and digital logic. However, many of these applications require that the carbon nanotubes be selectively placed onto specific areas of the device rather than producing a blanket film. The selective placement of carbon nanotubes can be challenging.
The low solubility of carbon nanotubes in most solvents provides one notable challenge. For instance, when the solvent is water, techniques have been proposed to wrap the carbon nanotubes in poly(thiophene)s which aids in dispersing the carbon nanotubes. The poly(thiophene)s have charged side chains which aid in the selective placement of the carbon nanotubes on a selectively charged surface. See, for example, U.S. Patent Application Publication Number 2014/0363643 by Afzali-Ardakani et al., entitled “Surface-Selective Carbon Nanotube Deposition Via Polymer-Mediated Assembly.” These techniques are however limited to the specific type of solvent.
Techniques have been proposed for dispersing carbon nanotubes in solvents such as toluene by wrapping the carbon nanotubes in a polymer poly(9,9-dioctylfluorenyl-2,7-diyl). This permits effective dispersion of the carbon nanotubes in the solvent. See, for example, Nish et al., “Highly selective dispersion of single-walled carbon nanotubes using aromatic polymers,” Nature Nanotechnology, vol. 2, pgs. 640-646 (October 2007) (hereinafter “Nish”). To date, however, no effective techniques exist for selective placement of carbon nanotubes from dispersions made in organic solvents such as toluene.
Therefore, improved carbon nanotube selective placement techniques would be desirable.